Metal-free synthesis of novel biobased dihydroxyl-terminated aliphatic polyesters as building blocks for thermoplastic polyurethanes

2011 ◽  
Vol 49 (13) ◽  
pp. 2959-2968 ◽  
Author(s):  
Donglin Tang ◽  
Bart A. J. Noordover ◽  
Rafael J. Sablong ◽  
Cor E. Koning
Keyword(s):  
Building Blocks ◽  
Aliphatic Polyesters ◽  
Metal Free ◽  
Thermoplastic Polyurethanes

Formation of Carbon-Oxygen Bond Mediated by Hypervalent Iodine Reagents Under Metal-free Conditions

2020 ◽  
Vol 17 ◽  
Author(s):  
Ayesha Jalil ◽  
Yaxin O Yang ◽  
Zhendong Chen ◽  
Rongxuan Jia ◽  
Tianhao Bi ◽  
...  
Keyword(s):  
Natural Products ◽  
Bond Formation ◽  
Building Blocks ◽  
Review Article ◽  
Hypervalent Iodine ◽  
Metal Free ◽  
Bioactive Natural Products ◽  
The Past ◽  
Oxygen Bond ◽  
Privileged Scaffolds

: Hypervalent iodine reagents are a class of non-metallic oxidants have been widely used in the construction of several sorts of bond formations. This surging interest in hypervalent iodine reagents is essentially due to their very useful oxidizing properties, combined with their benign environmental character and commercial availability from the past few decades ago. Furthermore, these hypervalent iodine reagents have been used in the construction of many significant building blocks and privileged scaffolds of bioactive natural products. The purpose of writing this review article is to explore all the transformations in which carbon-oxygen bond formation occurred by using hypervalent iodine reagents under metal-free conditions

scholarly journals Azaborabutadienes: Synthesis by Metal-Free Carboboration of Nitriles and Utility as Building Blocks for B,N-Heterocycles

2016 ◽  
Vol 128 (47) ◽  
pp. 14938-14942 ◽  
Author(s):  
Lingbing Kong ◽  
Wei Lu ◽  
Yongxin Li ◽  
Rakesh Ganguly ◽  
Rei Kinjo
Keyword(s):  
Building Blocks ◽  
Metal Free

Effective Approach toward Conjugated Porous Organic Frameworks Based on Phenanthrene Building Blocks: Metal-Free Heterogeneous Photocatalysts

2020 ◽  
Vol 12 (13) ◽  
pp. 15108-15114
Author(s):  
Cristina Monterde ◽  
Mercedes Pintado-Sierra ◽  
Rodrigo Navarro ◽  
Félix Sánchez ◽  
Marta Iglesias
Keyword(s):  
Building Blocks ◽  
Metal Free

scholarly journals 1,3-Dioxolan-4-Ones as Promising Monomers for Aliphatic Polyesters: Metal-Free, in Bulk Preparation of PLA

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2396
Author(s):  
Stefano Gazzotti ◽  
Marco Aldo Ortenzi ◽  
Hermes Farina ◽  
Alessandra Silvani
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Acid Catalyst ◽  
Monomer Conversion ◽  
Reaction Conditions ◽  
Aliphatic Polyesters ◽  
Metal Free ◽  
Weight Growth ◽  
Double Activation

The first example of solvent-free, organocatalyzed, polymerization of 1,3-dioxolan-4-ones, used as easily accessible monomers for the synthesis of polylactic acid (PLA), is described here. An optimization of reaction conditions was carried out, with p-toluensulfonic acid emerging as the most efficient Brønsted acid catalyst. The reactivity of the monomers in the tested conditions was studied following the monomer conversion by 1H NMR and the molecular weight growth by SEC analysis. A double activation polymerization mechanism was proposed, pointing out the key role of the acid catalyst. The formation of acetal bridges was demonstrated, to different extents depending on the nature of the aldehyde or ketone employed for lactic acid protection. The polymer shows complete retention of stereochemistry, as well as good thermal properties and good polydispersity, albeit modest molecular weight.

Comparison of Adipic Versus Renewable Azelaic Acid Polyester Polyols as Building Blocks in Soft Thermoplastic Polyurethanes

2016 ◽  
Vol 93 (11) ◽  
pp. 1529-1540 ◽  
Author(s):  
Norhayati Mohd Noor ◽  
Aisa Sendijarevic ◽  
Vahid Sendijarevic ◽  
Ibrahim Sendijarevic ◽  
Tuan Noor Maznee Tuan Ismail ◽  
...  
Keyword(s):  
Azelaic Acid ◽  
Building Blocks ◽  
Thermoplastic Polyurethanes

Metal-Free Halogenation of N-Substituted Enaminoesters and Enaminones: A Facile Access to Functionalized α,α-Dihaloimines

Synthesis ◽  
2020 ◽  
Vol 52 (08) ◽  
pp. 1301-1314 ◽  
Author(s):  
Changfu Qiu ◽  
Heshui Yu ◽  
Chuanjiang Qiu ◽  
Fangyi Li ◽  
Tongchuan Suo ◽  
...  
Keyword(s):  
Transition Metals ◽  
Building Blocks ◽  
Synthetic Method ◽  
Safe Operation ◽  
Reaction Conditions ◽  
Metal Free ◽  
Synthetic Utility ◽  
General Method

An efficient and general method for the synthesis of functionalized α,α-dihaloimines via halogenation of N-substituted enaminoesters and enaminones is described. This reaction, in which both α,α-dihaloimines and mixed α,α-dihaloimines could be achieved in good to excellent yields, is believed to proceed via an α-monohalogenated enamine intermediate. This synthetic method features no use of transition metals, readily accessible substrates, mild reaction conditions, simple and safe operation, and gram scale synthesis. Furthermore, the synthetic utility of the products was demonstrated by their efficient transformations to further useful nitrogen-containing heterocycles and building blocks.

Formation of Carbon-Nitrogen Bond Mediated by Hypervalent Iodine Re-agents Under Metal-free Conditions

2020 ◽  
Vol 24 ◽  
Author(s):  
Yaxin O Yang ◽  
Xi Wang ◽  
Jiaxi Xiao ◽  
Yadong Li ◽  
Fengxia Sun ◽  
...  
Keyword(s):  
Building Blocks ◽  
Review Article ◽  
Hypervalent Iodine ◽  
Coupling Reactions ◽  
Organic Transformations ◽  
Metal Free ◽  
Bond Forming ◽  
The Past ◽  
Oxidative Coupling Reactions ◽  
Nitrogen Bond

: In the past several decades, hypervalent iodine chemistry has witnessed prosperous development as hypervalent iodine reagents have been widely used in various organic transformations. Specifically, hypervalent iodine reagents have been vastly used in various bond-forming reactions. Among these oxidative coupling reactions, the reactions involving the formation of C-N bond have been extensively explored to construct various heterocyclic skeletons and synthesize various useful building blocks. This review article is to summarize all the transformations in which carbon-nitrogen bond formation occurred by using hypervalent iodine reagents under metal-free conditions.

Medicinally Relevant Modification of the Isoquinoline-1,3-dione Scaffold via Metal-Free Arylation and Fluorination of Diazo Homophthalimides­ in Brønsted Acids

Synthesis ◽  
2019 ◽  
Vol 51 (20) ◽  
pp. 3815-3824 ◽  
Author(s):  
Andrei Golushko ◽  
Dmitry Dar’in ◽  
Grigory Kantin ◽  
Natalia Guranova ◽  
Aleksander V. Vasilyev ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Fluorine Atom ◽  
Building Blocks ◽  
Bronsted Acids ◽  
Metal Free

Protonation of 4-diazoisoquinoline-1,3(2H,4H)-diones in Brønsted acids gives rise to diazonium cations that can be trapped with arenes to give 4-arylisoquinoline-1,3(2H,4H)-diones (homophthalimides). This provides a new, metal-free approach to 4-aryltetrahydroisoquinolines (obtainable from respective homophthalimides by reduction). Similarly, a fluorine atom can be introduced by trapping the diazonium cation with HF. This led to the preparation of the first examples of 4-monofluoro-substituted isoquinoline-1,3-diones (as well as their 4-bromo-4-fluoro and 4-chloro-4-fluoro variants), important carboxylic acid isosteres on their own and precursors of useful 4-fluorotetrahydroisoquinoline building blocks.

scholarly journals Azaborabutadienes: Synthesis by Metal-Free Carboboration of Nitriles and Utility as Building Blocks for B,N-Heterocycles

2016 ◽  
Vol 55 (47) ◽  
pp. 14718-14722 ◽  
Author(s):  
Lingbing Kong ◽  
Wei Lu ◽  
Yongxin Li ◽  
Rakesh Ganguly ◽  
Rei Kinjo
Keyword(s):  
Building Blocks ◽  
Metal Free
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